Heat and pressure sealing apparatus



June 8, 1954 P. MERCER HEAT AND PRESSURE SEALING APPARATUS Original Filed Dec. 14, 1950 7 INVENTOR.

Patented June 8, 1 954 2,680,471 HEAT AND PRESSURE SEALING APPARATUS Lewis P. Mercer, Milprint, Inc., of Delaware Original application December Inglewood, Calif., assignor to Milwaukee, Wis.,

a corporation 14, 1950, Serial No. 200,735. Divided and this application September 28, 1953, Serial No. 382,762

6 Claims. (Cl. 15442) apparatus for effecting transverse seals in multiple-ply ribbons or tubes of thermo-plastic material or the like.

This application is a division of my copending application Serial No. 200,735, filed December 14, 1950; and the primary object of this invention is to provide an improved simple, compact and highly apparatus for rapidly transversely sealing desired local portions of advancing tubes or superimposed ribbons of heat-sealable sheet material.

It has long been common practice in the packaging field to form commodity bags of thermoplastic sheet materials such as Pliofilm adapted to seal upon application of heat and pressure Without need for using glue or other separate adhesives. In the manufacture of such bags, it is customary to first form a flat longitudinally seamed or a seamless extruded tube of the material and to thereafter provide transverse seals at predetermined spaced points along the tube which may be severed adJacent to each of such ing operation to thereby provide a plurality of bags each having a seamed bottom. While the formation of the longitudinal side seam of the tube poses no particular problem because various types of apparatus may obviously be readily desealing as the tube is It is therefore a more specific object of the present invention to provide an improved apparatus for effecting transverse seals in advancing tubes or multiple-ply ribbons of thermoplastic materials by application of heat and pres- Another specific object of my invention is to provide an improved apparatus for efiecting A further specific on is to provide an improved apparatus of efadvancthereacross for the heating operation.

I An additional specific object of the present invention is to provide improved apparatus for Fig. 2 is a perspective view of a somewhat distended section of tubing prior to the transverse sealing thereof; and

Fig. 3 is a similar perspective view of the tube section after the transverse sealing of one end thereof with theaid of .the improved apparatus:

to form a commodity bag;

While the improved apparatus has been particularly described herein as being especially advantageously applicable in the continuous .produc.-., tion of commodity bags formed of thermoplastic" sheets folded to tubular formation. and -.having..a

lized to advantage in joining multiple-ply ribbons of diverse heat-sealable materials for other purposes; and it is also contemplated that 'certaini specific descriptive terms .used herein be given the-broadest possible interpretation consistent with..the disclosure.

In the commercial exploitation of the present invention, I prefer to utilize an installation sub-.x stantially like that shown diagrammatically in. 4

the accompanying drawing, especially in the pro-" duction of commodity bags .from sections of flattened tubing. Referring to the drawing, the initialsections of multiple-ply ribbons or flattened tubes 5 of thermoplastic sheet material out to the desired lengths may be supplied in any suitable manner successively to a ieed-conveyor B from which they are longitudinally fed in .timed succession tangentially to an arcuate pathformed by suitable means such as the -pe-- riphery of a drum 1, means such as a transverse heating element or bar 3 carried by thexdrum I and formed for cooperation with thesuccessive sections of the longitudinally advancing ribbons for subjecting predetermined local portionsiof. oneside thereof to heat transverselythereacross... throughout the travel of each section 5 along the arcuate path formed'by the periphery: of the drum '1, and means such as a flexible belt .or continuous band 9 for simultaneously applying resilient pressure to the other side-of thetade.

vancing sectionsin opposition to the heating means throughout the heating operation;

The heating element 8 andlbelt 9 cooperateto simultaneouslyapply heat andpressurerito one" end.portion of each of the thermo-plastic..orheat-scalable ribbons 5 for a prolonged-periodof. time and throughout the travel thereof along the arcuate path to thereby provide transverse. 1

seals it) entirely across the successive ribbon-seem tions 5 as thesesections leave the arcuate-pathgw and thefinally sealed ribbon sections-maythen be advanced tangentially from the drumperiphery longitudinallyjto a stacker. Has-shown in Fig.1, each of such sections 5 assuming the form.

of a flattened bag havinga transverse bottom seal 10 as shown in Fig; 3 and a previously formed longitudinal side seam l2 if seamed tubing. hasbeen 'used as shown.

less belts. l3 eachdriven abouta pair. of suitable spaced pulleys Hi and between which the sections 5. may be successively longitudinally advanced'in a straight line plane leadingtangentially to the drum periphery as shown; and for proper. operation, the operating. speed of the conveyor 6 must besynchronized-with thatpof. theheating element or elements 8 so that the:

transverse. seal ill will be effected .at-the desired-.3.

The feeding device 6 may preferablyconsist of a pair of cooperable. end-.-

5. To facilitate timing and advancement of the heating elements 8 along a given arcuate path, it is preferable to mount the cylindrical drum 1 for rotation about a central axis 15 as shown with the drum being provided with one or more of "the heating elements 8; disposed-about and extending transversely across the periphery thereof for rotation therewith, each of the heaters being adapted to transversely contact a predeterminedportion of one of the advancing ribbon sections 5 and to remain in contact therewithiduring iitssentire. travel along the arcuate orsemi-circular. pathfor approximately the distance of one: half of the circumference of the drum...-.The..belt..9, of course, is flexible and is alsolppreferably somewhat resilient, and this belt is preferably driven-by suitable means such as a drive roller I6 about pulleys 11 in such a manner as to remain in contact with the one side or external ply of the ribbon 5 throughout the heating operation, thereby efiecting simultaneous applicationof resilient. pressure 1n oppositionto each of the'heatingelements 8 throughout the period of contact of such elements with the bon.@It is particularly important to note that i the pressure applying belt 9 as used herein is of a different length than'the circumference of the drum? carrying the heating-elements 8so thatze a different portion of the belt is placed in op-. position :to .each heating element as the next successive seal 18 is effecteithereby subjectingv the belt 9 to minimumheat and weanand as-.

suring a more :uniforrn heat' application: in each;

operation.

Fromthe foregoing-detailed description, it will be apparent that. the present invention providesw; an improved apparatus for commercially .efiect-. ing transverse'seals at predetermined portions of multiple-ply ribbon sections of thermoplastic or heat-sealablesheet material and which is espeezcially extremely simpleand highly efficientin w therapid. and continuous production of com-; modity bags or the like.

trated: by. dot-and-dash lines in Fig.

nevertheless. be produced .at minimum temperatures'and at a maximum rate of speed- Furthercircumference of the drum 1, minimum wear will result and constantly uniform heat will be appliedat each seal because of the fact that a difierent portion of the belt 9 will be opposed to the heating element a during successive heating.

operations. While four equally spaced heaters 8 have been shownherein, the number of such heaters may obviously be varied as desired with I out departing from the invention; and if desired, the feed conveyor 6 may also be modified.

Through utilization of the improved apparatus, commercial-production of bags or like flexible containers: may be carried out in a continuous locality of the advancing tube or ribbon-asectionszfi manner underreadily controllable conditions witlr Since the heat-andpressure" for effecting the successive seals i9. is applied for. a prolonged period of time, as illus-.

1, :Vithr-I out in :anyway slowing or disrupting the con tinuons advancement of the successive ribbon or tubing sectionsii, the resultant seals possess, maximum durability. and strength. and they may.

minimum attention, and the apparatus herein described may be operated by a novice and has, in fact, proven highly successful in actual commercial use. The apparatus is furthermore exoperated upon merely by varying the rate at which the sections are fed to the conveyor 6 in an obvious manner. While the heat sealers 8 have been shown and described as operating on the leading ends of the successive sections 5 for efiecting the transverse seals, it is apparent that the device would operate with equal erfec- .l

with the ribbons for subjecting local portions of one side thereof to heat transversely thereacross throughout the travel of the ribbons over the drum periphery, and means for simultaneously applying resilient pressure to the other side of the ribbons throughout the heating operation.

2. Apparatus for efiecting transverse seals at predetermined portions of multiple-ply ribbons of thermo-plastic sheet material, comprising, a cylindrical drum, means for continuously longitudinally advancing the ribbons over the arcuate periphery of said drum, a heating element carried by said drum and movable with the ribbons for subjecting local portions of one side thereof to heat transversely thereacross throughout the travel of the ribbons over the drum periphery, and a belt movable with the ribbons over the periphery of said drum for simultaneously applying resilient pressure to the other side of the ribbons throughout the heating operation.

3. Apparatus for effecting transverse seals at predetermined portions of multiple-ply ribbons of thermo-plastic sheet material, comprising, a rotatable cylindrical drum, means for continuously longitudinally advancing the ribbons tanment therewith along an arcuate path, a transverse heating element carried by said drum for rotation therewith for subjecting local portions sure thereto throughout the heating operation.

4. Apparatus for effecting transverse seals at predetermined portions of multiple-ply ribbons of thermo-plastic sheet material, comprising,

pressure thereto throughout the heating opera tion, said belt being of a different length than the circumference of said drum.

5. Apparatus for eifecting transverse seals at predetermined portions of a multiple ply ribbon of thermoplastic sheet material, comprising, a cylindrical drum, means for longitudinally advancing the ribbon over the arcuate periphery of the ribbon over the drum periphery, and means for simultaneously applying resilient pressure to the other side of the ribbon throughout the heat ing operation.

6. Apparatus for eifecting transverse seals at predetermined portions of a multiple ply ribbon of thermoplastic sheet material, comprising, a carrier member having a cylindrical surface, means for longitudinally advancing the ribbon in contact with the cylindrical surface of said carrier member, a heating element revolvable with said cylindrical member surface and cooperable with the side of said ribbon facing said member surface for subjecting a local portion of said ribbon side to heat transversely thereacross, and means for simultaneously applying resilient pressure to the other side of the ribbon in opposition to said heating element.

No references cited. 

